Bulgaria's government on Wednesday approved the formation of a special unit to investigate high-level corruption, seeking to convince the European Union it is serious about tackling graft.

Brussels has repeatedly criticized the Balkan country for failing to jail corrupt officials or overhaul its inefficient judiciary. Bulgaria and neighboring Romania hope progress in these areas will lead to them being allowed to join the EU's Schengen zone, in which passport-free travel is permitted.

Corruption has undermined Bulgarians' trust in public institutions and has long deterred foreign investment.

"The approach will be the same for everyone from now on, no matter if it is a high-level official or someone who works at a lower level," Deputy Prime Minister Meglena Kuneva told reporters. "We must end checks that are not genuine."

The anti-graft bureau is to become operational by the start of 2016, in line with the National Strategy for Prevention and Combating of Corruption 2015-2020.

Tackling corruption and reforming the judiciary are among the pledges made by Prime Minister Boiko Borisov, who returned to power after a snap election in October.

Kuneva said top posts, including the president, prime minister, lawmakers and prosecutors, could be targets of investigation. Municipal councilors, directors of hospitals and border customs bosses could also fall under the unit's radar.

All government officials will have to make annual personal statements and provide details of their spouses' and children's assets and interests.

Kuneva has repeatedly said Bulgaria wants to emulate Romania, where senior politicians including former Prime Minister Adrian Nastase and prominent businessmen have been jailed.

The two Black Sea states joined the EU in 2007. Concern over the state of their judiciaries prompted Brussels to create the Co-operation and Verification Mechanism to track the progress of judicial reform and the fight against corruption.